1. Technical Field
The invention relates to the art of landscape materials and methods for making such materials More particularly, the invention relates to a method for making a landscape material, such as mulch, in a thinner and generally more uniform form than prior art mulch, which produces desirable characteristics in the resulting landscape material.
2. Background Art
In the landscape industry, natural fibrous material, such as mulch, is often placed around buildings, bushes, trees, stones, and other items. The mulch is typically made by grinding wood down to relatively small fibers. The wood that is used to make the mulch may be obtained from several different sources, including newly-cut trees, lumber, and scrap wood, such as old shipping pallets More particularly, in the prior art, generally large pieces of wood are placed in the feed hopper of a wood chipper or grinder, or on a conveyor leading into the grinder. The feed hopper or conveyor leads to the cutting chamber of the grinder, which includes multiple rotating heavy-duty teeth. Each large piece of wood is fed into the cutting chamber of the grinder from the feed hopper or conveyor, and the rotating teeth shred and cut the wood until it is reduced to small chunks, or mulch fibers.
Typically, a screen is placed over the exit area of the grinder, which keeps the wood in the cutting chamber of the grinder until it is reduced to a size that will pass through the openings in the screen. Depending on the size and configuration of the openings in the screen, the mulch fibers that are produced may be relatively large and coarse, or relatively small and fine. For example, each opening in a screen that is configured for coarse grinding is relatively large, such as from about 1.5 to about 2.5 inches in diameter, while each opening in a screen that is configured for fine grinding is relatively small, such as about 0.25 inches in diameter. Thus, coarse mulch may be up to about 0.5 inches in diameter, and is normally up to about 3.0 to about 4.0 inches long, while fine mulch may be up to about 0.25 inches in diameter, and is normally up to about 2.0 to 3.0 inches long. However, it is important to note that the random shredding and tearing of the wood by the teeth in the grinder results in fibers that are not uniform. That is, the resulting mulch fibers may have a maximum diameter as determined by the size of the openings in the exit screen, but the fibers are often below that maximum diameter due to the splintering of the wood as it is shredded and torn by the grinder teeth. As a result, both coarse mulch fibers and fine mulch fibers of the prior art typically randomly range in diameter and length. It is to be noted that reference herein to diameter for a cross-sectional measurement of mulch fibers is for the purpose of convenience, as such cross-sections include shapes other than those that are round, such as rectangular, square, random, etc., and all such cross-sectional shapes are included herein.
Coarse mulch and fine mulch, and particularly the fine mulch, are well-known in the art and typically are placed around bushes, plants, trees, and other items. A finer size range for mulch is desirable around bushes, plants and trees, as the mulch retains soil moisture, thereby encouraging growth of the bush, plant or tree, and inhibits weed growth. Specifically, a more fine-sized mulch enables easier placement of the mulch around bushes, plants and trees, which in turn provides increased coverage of the soil to retain more soil moisture, and to provide increased inhibition of weed growth. The finer-sized mulch is also softer to the touch than more coarse fibers, and is thereby more desirable to certain users. In addition, the finer mulch fibers often have a more desirable appearance than mulch with more coarse fibers. It should also be noted that finer mulch fibers that are more uniform in size are often more desirable to users, since the uniform fibers are often easier for a user to handle, and have a mole desirable appearance than fibers which vary greatly in size
To continue to increase the favorable properties of fine mulch fibers, it is desirable to reduce the cross-sectional area of the prior-art fine fiber size even more, and to create a more uniformly sized mulch fiber, while retaining enough fiber size to allow the mulch to be easily handled and resist premature decomposition. More particularly, if the prior-art fiber size is altered in a disadvantageous manner, the cross-sectional area and/or length of the mulch fibers may become too small, creating fibers that are difficult for a user to handle, may decompose prematurely, and/or may blow away If the cross-sectional area and/or length of the mulch fibers becomes too large, fibers would be created that are difficult for a user to spread and/or may be visually unappealing. Grinding machines of the prior art, due to their use of multiple rotating teeth to chip away at wood, typically produce such undesirable mulch fibers if they are used to attempt to reduce the size of the mulch beyond the typical prior-art non-uniform fine fiber size.
As a result, a need exists to decrease the cross sectional area of prior-art mulch fibers and to create mulch fibers that are more uniformly sized, in order to increase the desirable characteristics of the mulch, such as increased placement ability, increased softness, and a desirable appearance, without undesirably creating a mulch that is difficult to handle, or decomposes prematurely. The present invention satisfies this need by providing a landscape material with such decreased cross-sectional area and increased generally uniform size, and a method for making that material.